This site is a collation of descendants of Christopher Gettig of Northumberland County, Pennsylvania.
The information comes from various Gettig descendants, both in my line and others.
Some researchers state that Christopher immigrated from Sachsen, Germany (Saxony) by way of England. Other researchers place his birth in Pennsylvania. Unfortunately, none provide source citations. Once we start to see them on the census record they are in Northumberland Co. At this period in United States history, this isn't a very precise location. In these maps drawn by the Historical and Museum Commission of Pennsylvania we can see that, during Christopher's and Anna's lifetime, Northumberland (#10 in pink) went from the largest county in the state, covering almost a third of its territory, to its present size as one of the smallest counties. However, they seem to be localized in the area of Sunbury. This sits where the Susquehanna river splits in the middle of the western edge of the county's current borders.
If Christopher was from Saxony, we can see its locationon the following map of that time period, located directly in between Prussia and Austria.